Tension device for sewing-machines



(No Model.)

C. R. EDWARDS.

TENSIOLI D EVIG BPOR SEWING MACHINES. No. 299.629. PdtentedJune 3, 1884.

a 61,969: I I I daw'ew/zw' 4 w h a;

EINHED STATES OHARLES R. EDWARDS, OF BUFFALO, NEW YORK.

TENSION DEVICE FOR SEWING-MACHINES.

SPECIFICATION forming part of Letters Patent No. 299,629, dated June 3,1884.

Application filed September 6, 1883. (No model.) i

To aZZ whom, it may concern Be it known that 1, CHARLES R. EDWARDS, a

. citizen of the United States, residing at Bufia 10, in the county ofErie and State of New York, have invented certain new and usefulImprovements in Tension Devices for Sewing Machines; and I do herebydeclare the following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the art to which itappertains to make and use the same, reference being had to theaccompanying drawings, and to letters or figures of reference markedthereon, which form a part of this specification.

My invention relates more particularly-to an arrangement of tensiondevices in which a tension screw or nut is turned to regulate thetension of the sewing-thread.

The objects of my invention are, first, to provide a convenient meansfor.locking the action of the tension-screw within a range between adesirable maximum and minimum tension, and to change degrees of tensionwithin that range second, to arrange tension-plates so that the threadwill enter between them at a' lighter and more elastic tension than atits point of escape; third, to provide improved devices for allowing theliberation of the thread from the action of the tension-plates withoutobjectionable displacement of the plates or other parts affecting-asteady tenslon.

In the drawings, Figure 1 is a side elevation of my improvements. Fig. 2is a top plan view of the same. Fig. 3 is a fragmentary section ofFig. 1. Fig. 4 is a modification.

Referring to the drawings, a is the frame upon which the tension devicesare secured, and may be attached to or cast upon the arm of thesewing-machine. Upon this frame a are the two standards a and a 6 is theupper plate, which may be made more or less elastic, and one end may beheld in place by the top of screwp'ost c, which enters a hole in theplate I), such plate resting on the shoulder a of the post 0, as moreclearly shown in Fig. 3, in which the post and plate are shown in raisedposition. The opposite end of plate b is preferably shown as held fromany considerable lateral displacement by -means of the slot binits-turned-up end, which slot contains the thread-guide d, rigidlysecured to the standard a.

c is the tension-screw, which passes through a hole in the plate I) andenters the standard a This tension-screw has a shoulder, which bearsagainst the upper face of plate I), by which means the plate can bedepressed, as desired. f is the under plate, which is riveted orotherwise secured at its end to the standard a, from which point offastening the remaining portion of this plate extends toward thetension-screw, and is free to yield under pressure of the upper plate,I), on turning the tension-screw. The free end f of the plate f is moreelastic than the upper plate, in order that the thread may enter betweenv the plates at a lighter tension than at its point of escape, anyunevenness of the thread thereby presenting less obstruction, and thetwist of the thread less disturbed. The thread g, in its course fromthe. spool toward the needle, enters between the plates in the slot h ofthe plate I) and escapes from the plates on therear side of thethread-guide d. To keep the thread constantly in the same path whilebetween the plates, the slot h should have its inner end, h, so locatedthat the thread in passing from the spool and in front of thetension-screw should bear slightly against the inner end, h, of slot hand against the rear side of thread-guide d as it passes to the needle.

k is a lever pivoted upon the side of standard a, just below the underplate, f. An opening, Z, in the under plate, f, permits the lever is tobe pushed against the upper plate, I), to re lease the thread from itstension while drawing the fabric from under the needle. The tensionscrew6 is provided with a stop projection or finger, e, which strikes aprojection or stop, to

' prevent the tension-screw from making more than one revolution, andthus to limit the tension within a desirable range. In Figs. 1 and 2 theadjustable screw 0, before described, forms the stop for the finger e.

A- modified form of stop is shown in Fig. 4,in which m is an adjustableslotted plate adapted to be secured in'a raised or lowered position withrelation to stop-finger e by the set-screw m, which passes through theslot in the plate and into the standard a". The stop cor m is to belowered until the tensionscrew c has been I turned down to depress theupper plate, f, in order to obtain the lightest tension desired. Thenthe stop 0 or m is to be raised till the stopfinger 0 will strike it inbeing turned either way. In order that the stop-finger a may start justat the stop eat the desired light tension, the shoulder c, if necessary,may be raised by turning screw-stop c, to obtain at the start thedesired tension.

For convenience in adjusting the proper ten sion within the fixed range,I have placed upon the top of the tension-screw e figures indicatingdifferent degrees of tension. 'Ihese figures may start with figure 9facing the stop indicating a tension light enough for X0. 90 thread,and,as' the tension is tightened by turning screw 0, figure 8 will nextface the stop indicating No. 80 thread, and so on with the remainingfigures. Any of these figures maybe used to restore an y favoritetension for particular work without regard to the particular threadindicated.

To produce the most desirable degrees of exactness, the indicatingcharacters are useful; but a very desirable object is accomplished bynoting the position ofthe stop-finger or projection 0 on a tension screwor nut, as limited in its range within a single revolution for theposition ol'the finger, or its distance from thestarting-point on oneside of the stop is itself an important guide and this feature of thetension screw having the finger or projection to be met by theadjustable stop, it is evident, is applicable to any tension devicewhether tensionplates or tension-wheels are used, as in severalwe1l-known forms of tension devices where the tension is regulated byturning a thumb screw or nut. After the range of tension has been set,as described, the most inexperienced operator need not and cannot goastray from the best stitch.

I claim.

1. I11 a tension device for sewing-machines, the combination,with atensioirmember, of the tension-screw 0, provided with the stop finger orprojection c, and of a stop by means of which the stop-finger isrestricted in its movement to one revolution of the tension-screw, asand for the purpose stated.

2. I11 a tension device for sewing-machines, the combination ,with atension-member, ol'the tension-screw 0, provided with indicating-figuresand the stop finger or projection e, and of a stop by means of which thestop-finger is restricted in its movement within a single revolution ofthe tension-screw, as and for the purpose stated.

8. In a tension device for sewing-machines, the combination of the platef, having its end at (Z immovably fastened to the supportingframe a, andthe plate I), having its forward end touching and bearing on thatportion of platef between its fastened end (I audits inner end,substantially as and for the purpose stated.

at. In a tension device for sewing-machines, the plate f, having its endimmovably secured to the supporting-frame a, and the plate I), havingits forward end touching and bearing on the elastic portion oftheplatefibetween its'l'astening at d and its inner end, in combinationwith the tension-liberating lever k, pivoted to frame a, and acting uponplate I) from beneath, and between the elastic end of platef and itsrigid fastening at d, substantially as and for the purpose stated.

5. In a tension device for sewing-machines, the tension-plate Z), incombination with the screw 0, provided with shoulder c, and thetensionserew 0, provided with stop-finger a, substantially as and forpurposes set forth.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

CHARLES R. EDWARDS.

W'itnesses:

XV. T. MILLER, O'r'ro Honnicn'.

